JP4813087B2 - Tapping machine - Google Patents

Description

  The present invention relates to a tapping processing apparatus that performs female screw stand on a workpiece by feeding and moving it in an axial direction while rotating a tap.

  The tapping device advances the spindle shaft while rotating it forward, brings the tap holder provided integrally with the tip of the spindle shaft so as to be able to rotate integrally with the workpiece, and moves the screw portion of the tap held by the tap holder to the workpiece. Is inserted into a pre-drilled screw hole and threaded. Then, when reaching the forward end, the spindle shaft is moved backward while rotating backward to separate the tap holder from the work, and the threaded part of the tap is extracted from the screw hole after threading to complete the screw hole in the work. Have.

  The tapping machine cannot perform threading if there is a workpiece defect such as no screw pilot hole is formed at all or the screw pilot hole is not completely formed, and the tap rotates excessively during tapping. Torque may break the tap thread, or an excessive load may act in the thrust direction and damage the tap shank.

  Therefore, when the tap holder is supported so as to be able to move relative to the spindle axis in the thrust direction, and the tap holder moves relative to the spindle axis during tapping, the preset reference movement amount is exceeded. In the past, a tapping apparatus for determining work abnormality has been proposed and put into practical use.

  A tap holder has been proposed that includes a slider that moves in the thrust direction when an overload is applied to the tap during tapping, and detects the overload applied to the tap by the movement of the slider (for example, a patent). Reference 1).

JP-A-8-108317

  However, according to the above-described conventional tapping processing apparatus, since the operation abnormality is determined based on the movement of the tap holder in the thrust direction with respect to the spindle shaft, the movement of the tap holder cannot be detected due to, for example, a failure of a sensor or the like. In such a case, abnormal operation cannot be determined, and the forward rotation of the spindle shaft is continued as it is, which may cause breakage of the thread portion of the tap or breakage of the shank portion.

  Further, the sensor that detects the movement of the tap holder in the thrust direction cannot detect whether the spindle shaft is actually rotating. Therefore, for example, even if the spindle shaft rotation speed is slowed down due to overload or the spindle shaft rotation stops due to tap engagement etc. There is also a possibility that the work cannot be determined and the work is determined to have been normally performed and the work is conveyed to a downstream process.

  Further, the sensor that detects the movement of the tap holder cannot grasp the amount of movement of the spindle shaft in the forward and backward directions. Therefore, for example, when the spindle shaft cannot be stopped at the forward end due to a brake failure in the rotation drive unit, and overruns, it is not possible to determine an abnormal operation, and the tapping of the tap due to a rear-end collision with the bottom of the screw hole, etc. There is a risk of breakage.

  The present invention has been made to solve at least one of the above problems, and an object of the present invention is to provide a tapping machine that can detect a work abnormality during tapping with a simple configuration.

  The tapping device according to the first aspect of the present invention that solves the above-described problem includes a base portion, a rotation shaft that is rotatably supported by the base portion, a rotation drive portion that rotates the rotation shaft forward and backward, and a rotation A spindle shaft that can be rotated integrally with the shaft and movable in the axial direction of the rotation shaft, and the spindle shaft is rotatably supported on the base portion, and is moved forward and backward at a feed pitch corresponding to forward rotation and reverse rotation. A feed moving portion that rotates integrally with the spindle shaft and is axially movable with respect to the spindle shaft so as to extend and contract in the axial direction at a position forward of the front end portion of the spindle shaft. A tap holder that can hold a tap having the same feed pitch as that of the feed moving unit, and is interposed between the spindle shaft and the tap holder to bias the tap holder in the extending direction. The biasing means and the protrusions provided on the tap holder and projecting radially outward of the tap holder and the recesses recessed radially inward of the tap holder are alternately formed along the rotation direction of the tap holder. The detector is supported by the base portion so as to be able to move forward and backward in synchronization with the spindle shaft, and is arranged at a position facing the detector at a radially outer position of the tap holder than the detector in a state where the tap holder is extended. And a detection sensor that outputs ON when approaching the protrusion and outputs OFF when separated from the protrusion, and a control unit that controls the rotation driving unit based on the output of the detection sensor.

  According to a second aspect of the present invention, in the tapping apparatus according to the first aspect, the control means measures an on-off interval between on and off that is output from the detection sensor by forward rotation driving of the rotation driving unit, The measured on / off interval is compared with a preset advance reference interval, and when the on / off interval exceeds the advance reference interval, it is determined that the operation is abnormal, and the forward rotation drive by the rotation drive unit is stopped.

  According to a third aspect of the present invention, in the tapping apparatus according to the first or second aspect, the control means measures an on / off interval between on and off output from the detection sensor by reverse rotation driving of the rotation driving unit. The measured on-off interval is compared with a preset reverse reference interval, and the reverse drive by the rotary drive unit is stopped when the on-off interval exceeds the reverse reference interval, and it is determined that the operation is abnormal. To do.

  According to a fourth aspect of the present invention, in the tapping apparatus according to any one of the first to third aspects, the control means uses a pair of on and off output from the detection sensor as one pulse, and the rotation drive unit Based on the number of detected pulses of the counted pulse and the number of times the protrusion of the detector approaches the detection sensor while the spindle shaft advances from the backward end to the forward end. Compared with the set forward reference pulse number, the detection sensor number is judged to be abnormal because the detected pulse number exceeds the forward reference pulse number before the spindle shaft advances from the backward end and reaches the forward end. It is characterized by that.

  According to a fifth aspect of the present invention, in the tapping apparatus according to any one of the first to fourth aspects, the control means uses a pair of on and off output from the detection sensor as one pulse, and the rotation drive unit Based on the number of detected pulses of the counted pulse and the number of times the protrusion of the detector approaches the detection sensor while the spindle shaft is retracted from the forward end to the backward end. Compared with the set backward reference pulse number, the detection sensor number is judged to be abnormal if the detected pulse number exceeds the backward reference pulse number before the spindle shaft moves backward from the forward end and reaches the backward end. It is characterized by that.

  According to a sixth aspect of the present invention, in the tapping apparatus according to any one of the first to fifth aspects, the control means uses a pair of on and off output from the detection sensor as one pulse, and the rotation drive unit The number of pulses detected until the spindle shaft stops moving forward after the spindle shaft reaches the forward end due to the forward rotation driving of the spindle is compared with the preset overshoot tolerance, and the number of detected pulses is When the value is exceeded, it is determined that the brake of the rotational drive unit is abnormal.

A seventh aspect of the present invention is the tapping apparatus according to any one of the first to sixth aspects, wherein the control means uses a pair of on and off output from the detection sensor as one pulse, and the rotation driving unit. The number of detected pulses of the pulse counted from when the spindle axis reaches the retracted end by reverse rotation driving until the spindle axis stops moving and the preset allowable return value are compared, and the number of detected pulses is returned. It is judged that the brake of the rotation drive unit is abnormal when the excess allowable value is exceeded.
The invention according to claim 8 is the tapping apparatus according to any one of claims 1 to 7, wherein the detection sensor is released from facing the detector in a state where the tap holder is contracted. Output off.

  According to the first aspect of the present invention, the rotary shaft is forwardly rotated by the rotation drive unit, so that the spindle shaft is moved forward at the same feed pitch as that of the tap while being forwardly rotated, and the tap holder is rotated forward together with the spindle shaft. In addition, by rotating the rotating shaft in the reverse direction with the rotation drive unit, the spindle shaft is rotated in the reverse direction at the same feed pitch as the tap, and the tap holder is rotated in reverse with the spindle shaft. It can be retreated while. Therefore, the tap held by the tap holder can be inserted into the screw pilot hole of the workpiece, moved forward while rotating forward in the screw pilot hole, and moved backward while rotating backward, so that the workpiece can be tapped.

  When the threaded hole of the workpiece is properly cut, the tap holder is extended and moved forward and backward in synchronization with the spindle shaft. In such an extended state, the detection sensor is arranged at a position facing the detector at a radially outer position of the tap holder than the detector, so that the protrusion of the detector is detected according to the rotation of the tap holder. The sensor is repeatedly approached and separated, and ON and OFF are alternately output from the detection sensor at predetermined intervals.

  On the other hand, when the protrusion of the detector cannot be detected due to a failure of the detection sensor or the like, the output of the detection sensor is kept off.

  Also, when the tap holder stops rotating due to the tap biting into the screw hole of the workpiece, etc., the protrusion of the detector is kept either in a state close to or separated from the detection sensor. The output is maintained either on or off.

  Further, if the tap is prevented from advancing due to reasons such as a screw pilot hole not being formed in the workpiece, a thrust load is applied to the tap, and the tap holder acts on the spindle shaft against the urging force of the urging means. In contrast, the position of the detector and the detection sensor is shifted in the axial direction, the opposing positions are released, the protrusion of the detector is separated from the detection sensor, and the output of the detection sensor is kept off. Is done.

  Therefore, when the output of the detection sensor turns on and off alternately at predetermined intervals, the control means rotates with the tap holder extended with respect to the spindle shaft, and the workpiece is properly threaded. As a result, it can be determined that the work is normal. When the output of the detection sensor is maintained at one of on and off, it can be determined that the operation is abnormal.

  When the control means determines that the operation is abnormal, the control means can control the rotation drive unit to stop the forward rotation or the reverse rotation of the rotation shaft. Therefore, breakage of the threaded portion of the tap and breakage of the shank portion can be prevented.

  According to the second aspect of the present invention, the control means measures the on / off interval of the detection sensor by the forward rotation drive of the rotation drive unit, compares the on / off interval with the forward reference interval, and the on / off interval is the forward reference. When the interval is exceeded, it is determined that the operation is abnormal, and the forward rotation drive by the rotation drive unit is stopped.

  Therefore, for example, when the hole diameter of the screw hole is smaller than the standard, the tap is overloaded, the tap holder's normal rotation speed is lower than usual, and the on / off interval exceeds the forward reference interval Therefore, it is possible to stop the rotational drive of the rotational drive unit by judging that the operation is abnormal.

  Also, when the rotation drive unit is driven to rotate forward, the tap holder stops rotating forward and the output of the detection sensor is maintained either on or off, or the tap holder contracts with respect to the spindle shaft and is detected. When the output of the sensor is kept off, the on / off interval exceeds the forward reference interval, and it is determined that the operation is abnormal, and the forward rotation drive of the rotation drive unit can be stopped. Accordingly, it is possible to prevent an overload from acting on the tap, and to prevent breakage of the threaded portion of the tap or damage to the shank.

  According to the third aspect of the present invention, the control means measures the on / off interval of the detection sensor by reverse rotation driving of the rotation driving unit, compares the on / off interval with the retreat reference interval, and the on / off interval is the retreat reference. When the interval is exceeded, it is determined that the operation is abnormal and the reverse rotation drive by the rotation drive unit is stopped.

  Therefore, for example, when the tap is overloaded when it is pulled out from the screw hole, the reverse rotation speed of the tap holder is lower than normal, and the on / off interval exceeds the retraction reference interval, it is determined that the operation is abnormal and the rotation is performed. The reverse rotation drive of the drive unit can be stopped.

  Also, when the reverse rotation of the tap drive is stopped and the reverse rotation of the tap holder is stopped and the output of the detection sensor is maintained either on or off, the on / off interval exceeds the reverse reference interval, It can be determined that there is an abnormality and the reverse rotation drive of the rotation drive unit can be stopped. Accordingly, it is possible to prevent an overload from acting on the tap, and to prevent breakage of the threaded portion of the tap or damage to the shank.

  According to a fourth aspect of the present invention, the control means starts counting pulses from the start of forward rotation driving of the rotation driving unit, with a pair of ON and OFF output from the detection sensor as one pulse. Then, the detected pulse number of the counted pulse is compared with the reference pulse number. The forward reference pulse number is set in advance based on the number of times the protrusion of the detector approaches the detection sensor while the spindle shaft moves from the backward end to the forward end. Then, when the number of detected pulses exceeds the reference number of pulses before the spindle shaft reaches the forward end, it is determined that the detection sensor is abnormal.

  When the spindle shaft advances from the retracted end to the advanced end, the number of detection pulses becomes the same as the number of times the protrusion of the detector approaches the detection sensor according to the rotation of the tap holder.

  Therefore, for example, by setting a value including an error in the number of times the protrusion of the detector approaches the detection sensor in accordance with the rotation of the tap holder as the forward reference pulse number, the spindle shaft moves forward from the backward end to advance the forward end. When the number of detected pulses is the same as the forward reference pulse number, the detection sensor is normal, and the detected pulse number is the forward reference value before the spindle shaft advances from the backward end and reaches the forward end. When the number of pulses is exceeded, it can be determined that the detection sensor is abnormal.

  According to the fifth aspect of the present invention, the control means starts counting pulses from the start of reverse rotation drive of the rotation drive unit, with one pair of on and off output from the detection sensor as one pulse. Then, the number of detected pulses of the counted pulse is compared with the number of backward reference pulses. The number of backward reference pulses is set in advance based on the number of times the protrusion of the detector approaches the detection sensor while the spindle shaft moves from the forward end to the backward end with the tap holder extended. Then, when the number of detected pulses exceeds the reference number of pulses before the spindle shaft reaches the backward end, it is determined that the detection sensor is abnormal.

  When the spindle shaft advances from the forward end to the backward end, the number of detection pulses becomes the same as the number of times that the protrusion of the detector approaches the detection sensor in accordance with the rotation of the tap holder.

  Therefore, for example, by setting a value including an error in the number of times the protrusion of the detector approaches the detection sensor in accordance with the rotation of the tap holder as the backward reference pulse number, the spindle shaft moves backward from the forward end and moves backward. When the number of detected pulses when reaching the number is the same as the number of backward reference pulses, the detection sensor accurately detects the protruding portion of the detector, and it can be determined that the sensor is normal.

  Also, if the number of detected pulses exceeds the reverse reference pulse number before the spindle shaft moves backward from the forward end and reaches the backward end, the detection sensor does not accurately detect the protruding part of the detector. It can be determined that the sensor is abnormal.

  According to the sixth aspect of the present invention, the control means sets the pair of on and off output from the detection sensor as one pulse, and after the spindle shaft reaches the forward end by the forward rotation drive of the rotation drive unit, the spindle shaft The detected number of pulses counted until the forward movement stops is compared with a preset overshoot tolerance, and if the detected pulse number exceeds the overshoot tolerance, it is determined that the brake of the rotary drive is abnormal. .

  As a result, it is possible to determine whether or not the spindle shaft has exceeded the amount of movement permitted in advance and has gone too far forward to determine whether or not the brake of the rotation drive unit is operating normally.

  According to the seventh aspect of the present invention, the control means sets the pair of on and off output from the detection sensor as one pulse, and after the spindle shaft reaches the retracted end by reverse rotation driving of the rotation driving unit, the spindle shaft Compare the number of detected pulses counted until the reverse of the motor stops and the preset allowable return value, and if the detected pulse number exceeds the allowable return value, the brake to decide.

As a result, it is possible to determine whether the spindle shaft has returned to the reverse side beyond the movement amount permitted in advance, and to determine whether the brake of the rotation drive unit is operating normally. .
According to the eighth aspect of the present invention, when the tap holder is contracted, the facing of the detector is released and OFF is output. Therefore, when the advancement of the tap is hindered due to, for example, a screw pilot hole not formed in the workpiece, the tap holder moves in a direction in which the tap holder contracts against the urging force of the urging means, The positions of the detector and the detection sensor are shifted in the axial direction so that the opposing portions are released, the protruding portion of the detector is separated from the detection sensor, and the output of the detection sensor is output OFF, and it is determined as abnormal.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall view for explaining the configuration of a tapping apparatus 1 according to the present embodiment, and FIG. 2 is a sectional view taken along line XX of FIG.

  As shown in FIG. 1, the tapping apparatus 1 includes a rotary shaft 11, a motor (rotation drive unit) 12, a spindle shaft 20, a screw feed mechanism (feed movement unit) 30, a tap holder 40, and a control means 50. Yes.

  In FIG. 1, reference numeral 2 denotes a base portion. The base portion 2 has a substantially flat plate shape, is attached to a base (not shown) of the tapping apparatus 1 installed on the floor surface, and extends in the vertical direction at a position above the workpiece W. It is provided to exist.

  A rotating shaft 11 extends in the vertical direction and is rotatably supported at a substantially central position of the base portion 2, and a motor 12 is attached to a side position of the rotating shaft 11.

  The motor 12 is a motor capable of controlling the rotation stop position, such as a step motor or a servo motor, for example. The motor 12 rotates the motor shaft 12a by a rotation angle set in advance according to a control command from the control means 50 to operate the brake. Thus, the rotation of the motor shaft 12a can be stopped at a predetermined rotation angle position.

  The motor shaft 12a and the rotating shaft 11 of the motor 12 are connected by a belt pulley 13 which is a power transmission means, and the rotation of the motor 12 can be transmitted to rotate the rotating shaft 11.

  In the belt pulley 13, the driving pulley 14 is attached to the motor shaft 12 a of the motor 12, the driven pulley 15 is attached to the upper end of the rotating shaft 11, and the belt 16 is connected to the driving pulley 14 and the driven pulley 15. It is spanned between and connected.

  The spindle shaft 20 has a cylindrical shape extending coaxially continuously below the rotation shaft 11. A spline hole (not shown) is formed in the rear end portion 21 located at the upper portion of the spindle shaft 20 in the direction of the central axis from the end face. The rotary shaft 11 is connected to the rotary shaft 11 so as to be movable in the vertical direction along the axial direction.

  A screw shaft portion 31 of a screw feed mechanism 30 that is a feed moving portion is formed on the outer peripheral surface of the rear end portion 21 of the spindle shaft 20. The screw feeding mechanism 30 includes a screw shaft portion 31 formed on the outer peripheral surface of the rear end portion 21 of the spindle shaft 20 and a screw bearing 32 attached to the base portion 2. The screw shaft portion 31 and the screw bearing portion 32 are screwed together with the same pitch as the tap T, and the spindle shaft 20 is rotatably supported on the base portion 2 and is tapped by forward and reverse rotation. The spindle shaft 20 can be moved forward and backward at the same feed pitch as T.

  The front end portion 22 of the spindle shaft 20 has a cylindrical shape extending downward from the base portion 2, and the rear end portion 41 of the tap holder 40 is inserted into the inner diameter hole 23 from below. The tap holder 40 is supported on the same axis.

  The tap holder 40 has a cylindrical shape extending coaxially continuously below the spindle shaft 20. A spline is formed at the rear end portion 41 located at the upper portion of the tap holder 40 and is inserted into the inner diameter hole 23 of the spindle shaft 20 so as to be fitted to the spindle shaft 20. The spindle shaft 20 is integrally rotatable and connected to the spindle shaft 20 so as to be movable in the axial direction. The spindle shaft 20 is provided so as to extend and contract in the axial direction at a position lower than the front end portion 22 of the spindle shaft 20.

  The front end portion 42 of the tap holder 40 is provided with a chuck 43 that detachably holds the tap T on the same axis. The chuck 43 includes a plurality of claw portions (not shown) that approach and separate toward the rotation center along the radial direction of the tap holder 40, and chucks the shank portion T <b> 1 of the tap T to The threaded portion T2 protrudes downward, and the tap T is configured to be detachably held so as to extend coaxially with the tap holder 40.

  Between the spindle shaft 20 and the tap holder 40, there is provided a coil spring 24 which is a biasing means for biasing the tap holder 40 in the direction in which the tap holder 40 extends. The coil spring 24 is accommodated in the inner diameter hole 23 of the spindle shaft 20 and presses the rear end portion 41 of the tap holder 40 downward.

  The tapping apparatus 1 having the above configuration is provided with a detector 51 and a detection sensor 54 that are characteristic components of the present invention.

  As shown in FIG. 1, the detector 51 is fixed coaxially with the tap holder at a position between the rear end portion 41 and the front end portion 42 of the tap holder 40. As shown in FIG. The disc 52 having a predetermined thickness in the axial direction of 40 has a basic shape and is cut out with a predetermined interval along the rotation direction, whereby the protruding portion 52 and the tap protruding outward in the radial direction of the tap holder 40 The recessed portions 53 that are recessed toward the radially inner side of the holder 40 are formed alternately along the rotation direction of the tap holder 40. In the present embodiment, the recessed portion 53 has an arc shape that has a constant radius of curvature and is recessed radially inward, and the four protruding portions 52 and the recessed portions 53 are alternately arranged in the rotational direction. Is formed.

  The detection sensor 54 is attached to the sensor bracket 55. The sensor bracket 55 is externally fitted to the front end portion 22 of the spindle shaft 20 through a rotation support member (not shown) such as a bearing, and is rotatably supported by the spindle shaft 20.

  The sensor bracket 55 is provided with an arm portion so as to protrude outward in the radial direction of the spindle shaft 20, and penetrates the arm portion so as to extend in parallel along the axial direction of the spindle shaft 20. A hole 56 is formed through.

  A rod-shaped shaft 3 extending in the vertical direction and having an upper end fixed to the base portion 2 is inserted into the through hole 56 of the sensor bracket 55, and the spindle shaft 20 is moved forward and backward. Thus, a rotation stopper that prevents the sensor bracket 55 from rotating with the spindle shaft 20 is configured. Therefore, the sensor bracket 55 and the detection sensor 54 attached to the sensor bracket 55 are supported by the base portion 2 so as to be able to move forward and backward in synchronization with the spindle shaft 20.

  The detection sensor 54 is supported by the sensor bracket 55 so as to face the detector 51 at a radially outer position of the tap holder 40 with respect to the detector 51 in a state where the tap holder 40 is extended, and according to the rotation of the tap holder 40. It arrange | positions in the position which repeats approach and separation | spacing with the protrusion part 52 of the detector 51. FIG.

  Then, the detector 51 is set to output ON when approaching the protruding portion 52 and output OFF when separated from the protruding portion 52.

  Thereby, for example, the detection sensor 54 rotates in a state where the tap holder 40 is extended and faces the protruding portion 52 of the detector 51 (see FIG. 2), thereby outputting “ON” and facing the recessed portion 53. Outputs off. Further, when the tap holder 40 is contracted, the position of the detector 51 is shifted in the axial direction, the opposing of the detector 51 is released, and the switch 51 is separated from the protruding portion 52 to output OFF. In the present embodiment, a proximity sensor that outputs ON when the detector 51 exists in a preset vicinity region is used as the detection sensor 54.

  In the drawing, reference numeral 58 denotes a forward end detecting means for detecting the forward end of the spindle shaft 20, and reference numeral 59 denotes a backward end detecting means for detecting the backward end of the spindle shaft 20. The forward end detecting means 58 and the backward end detecting means 59 are constituted by, for example, a proximity switch, a limit switch, and the like, and are respectively attached to the stay 4 that extends downward from the base portion 2. The forward end detecting means 58 is set to output ON when the spindle shaft 20 is located at the forward end, and to output OFF when the spindle shaft 20 is located at a position other than the forward end. The backward end detecting means 59 is set to output ON when the spindle shaft 20 is located at the backward end, and to output OFF when the spindle shaft 20 is located at a position other than the backward end.

  The control means 50 includes a sequence program computer, and stores a control program for performing tapping processing control so as to be executable. And it is connected to the detection sensor 54, the forward end detection means 58, the backward end detection means 59, the motor 12 and the like, and the tapping process control is performed by rotating the motor 12 based on the detection signal from the detection sensor 54 and the like. Do.

  Next, a tapping method by the tapping device 1 having the above configuration will be described below with reference to FIGS. FIG. 3 is a flowchart for explaining a tapping method by the tapping device 1, FIG. 4 is a diagram for explaining the operation of the tapping device 1 with respect to the workpiece W in which an appropriate screw pilot hole W1 is formed, and FIG. It is a figure explaining operation | movement of the tapping apparatus 1 with respect to the workpiece | work W in which the screw pilot hole W1 is not formed.

  As shown in FIG. 4A and FIG. 5A, the control unit 50 rotates the motor 12 forward when the workpiece W is positioned and fixed at a workpiece fixing position set in advance with respect to the tapping machine 1. The driving is started, and the motor shaft 12a is rotated in the direction in which the rotating shaft 11 is normally rotated at a preset rotation speed (step S1). The rotation of the motor shaft 12a is transmitted to the rotation shaft 11 via the belt pulley 13, and the rotation shaft 11 is rotated forward. The spindle shaft 20 is moved forward at the same feed pitch as the tap T by the screw feed mechanism 30 while the spindle shaft 20 is rotated forward by the forward rotation of the rotary shaft 11, and the tap holder 40 is moved forward to approach the workpiece W.

  The tap holder 40 moves forward with the spindle shaft 20 while rotating forward, and approaches the workpiece W while rotating the tap T in the threading direction. 4 (a) to 4 (c), with the tap holder 40 extended, the threaded portion T2 of the tap T is inserted into the screw pilot hole W1 of the workpiece W, and threading is started. .

  In such a case, in the detector 51, the protrusion 52 repeatedly approaches and separates from the detection sensor 54 according to the rotation of the tap holder 40, and ON and OFF are alternately output from the detection sensor 54 at a predetermined interval.

  Based on the on / off interval Ta, which is an on / off time interval output from the detection sensor 54 when the motor 12 is driven to rotate forward, the control means 50 determines whether or not the tapping process is abnormal (step S2).

  Here, the on / off interval Ta is compared with the advance reference interval Tf stored in advance in the control means 50. When the on / off interval Ta is equal to or less than the advance reference interval Tf (No in step S2), it is determined that the operation is normal. Then, the motor 12 continues to rotate forward. When the on / off interval Ta exceeds the forward reference interval Tf (Yes in step S2), it is determined that the operation is abnormal, and the forward rotation driving of the motor 12 is stopped (step S3).

  For example, when the screw portion T2 of the tap T is engaged with the screw under hole W1 and the rotation of the tap holder 40 is stopped, or when the hole diameter of the screw under hole W1 is smaller than the reference, an overload acts on the tap T. When the rotational speed of the tap holder 40 is reduced, the on / off interval Ta exceeds the forward reference interval Tf.

  Further, as shown in FIG. 5, when the screw pilot hole W1 is not formed in the workpiece W, the forward movement of the tap holder 40 is hindered and the screw portion T2 of the tap T is pressed against the workpiece W (see FIG. 5). 5 (b)). Accordingly, a thrust load is applied to the tap T, and the tap holder 40 moves relative to the spindle shaft 20 in the direction of contracting in the axial direction against the urging force of the coil spring 24. Then, the detector 51 moves together with the tap holder 40, the position with the detection sensor 54 is shifted in the axial direction (see FIG. 5C), and moves from the vicinity of the detection sensor 54 to the outside of the vicinity. Therefore, ON and OFF are not alternately output from the detection sensor 54, and the state of outputting OFF is maintained, and the ON / OFF interval Ta exceeds the forward reference interval Tf.

  Furthermore, when the detection sensor 54 fails and the approach and separation of the protrusion 52 cannot be detected, the output of the detection sensor 54 does not repeat on and off alternately, and either the on or off state is output. The on / off interval Ta is maintained and exceeds the forward reference interval Tf.

  Accordingly, in such a case, it is determined that the operation is abnormal, and the forward rotation drive of the motor 12 can be quickly stopped, and an overload is prevented from acting on the tap T, and the threaded portion T2 of the tap T is broken or the shank portion is prevented. T2 can be prevented from being damaged.

  Further, the control means 50 determines whether or not the detection sensor 54 is operating normally when the motor 12 is driven to rotate forward. Here, a pair of on and off output from the detection sensor 54 is set as one pulse, and counting of pulses is started from the start of forward rotation driving of the motor 12, and the number of detected pulses Pa of the counted pulses and the control means 50 in advance. The number of forward reference pulses Na stored in the inside is compared. The forward reference pulse number Na is set based on the number of times the protrusion 52 of the detector 51 approaches the detection sensor 54 while the spindle shaft 20 advances from the backward end to the forward end. In this embodiment, the forward reference pulse number Na is set. A value including an error is set in the number of times the protruding portion 52 approaches the detection sensor 54.

  The comparison between the detection pulse number Pa and the forward reference pulse number Na is performed every time the detection sensor 54 counts pulses (step S4). If the detected pulse number Pa is equal to or smaller than the forward reference pulse number Na as a result of the comparison between the detected pulse number Pa and the forward reference pulse number Na (No in step S4), is the forward end detecting means 58 turned on? (Yes in step S6) Or until the detected pulse number Pa exceeds the forward reference pulse number Na (Yes in step S4), the motor 12 continues to be driven in the forward rotation.

  If the detected pulse number Pa exceeds the forward reference pulse number Na before the forward end detecting means 58 detects ON, that is, before the spindle shaft 20 reaches the forward end (Yes in step S4). Then, it is determined that the detection sensor 54 is abnormal, and the rotation drive of the motor 12 is stopped (step S5). Thereby, the tapping process defect to the workpiece | work resulting from the malfunction of the detection sensor 54 can be prevented beforehand.

  Then, when the forward end detecting means 58 is turned on (Yes in step S6), the control means 50 stops the forward rotation drive of the motor 12 (step S7), and whether or not the brake of the motor 12 is operating normally. A determination is made (step S8). As a result, the overshoot movement amount at which the spindle shaft 20 has stopped after passing through the forward end is detected, and it is determined whether or not the brake is abnormal based on the magnitude of the overshoot movement amount.

  The control means 50 sets a pair of on and off outputs from the detection sensor 54 as one pulse, and pulses when the spindle shaft 20 reaches the forward end and the forward end detection means 58 is turned on by the forward rotation of the motor 12. Start counting.

  Then, the detected pulse number Pb counted until the forward movement of the spindle shaft 20 is stopped and the overshoot allowable value Nb previously stored in the control means 50 are compared, and the detected pulse number Pb exceeds the overshoot allowable value Nb. If it is (Yes in step S8), it is determined that the brake of the motor 12 is abnormal (step S9), and the tapping process is stopped, an error message is transmitted, a warning light is turned on, and the like.

  If the detected pulse number Pb is equal to or less than the overshoot allowable value Nb (No in step S8), it is determined that the brake of the motor 12 is operating normally, the reverse rotation drive of the motor 12 is started, and the rotating shaft 11 Is reversely rotated at a preset rotation speed (step S10).

  Due to the reverse rotation drive of the motor 12, the rotary shaft 11 is reversely rotated, and the spindle shaft 20 is retracted at the same feed pitch as the tap T by the screw feed mechanism 30, and is separated from the workpiece W while the tap holder 40 is reversely rotated. . The tap T moves backward while rotating in reverse with the tap holder 40, and the screw portion T2 is extracted from the screw prepared hole W1 after threading.

  The control means 50 determines work abnormality of the tapping work based on the on / off interval Tb that is the on / off time interval output from the detection sensor 54 by the reverse rotation driving of the motor 12 (step 11).

  The control means 50 compares the on / off interval Tb with the retreat reference interval Tr previously stored in the control means 50, and when the on / off interval Tb is equal to or less than the retreat reference interval Tr (No in step S11), the operation is normal. Judgment is made and the rotation drive of the motor 12 is continued. When the on / off interval Tb exceeds the retreat reference interval Tr (Yes in step S11), it is determined that the operation is abnormal and the reverse rotation driving of the motor 12 is stopped (step S12).

  For example, when the tap T is extracted from the threaded hole W1 after threading, the threaded portion T2 is engaged with the threaded hole W1 and the rotation of the tap holder 40 is stopped. When it decreases, the on / off interval Tb exceeds the retreat reference interval Tb.

  Therefore, in such a case, it can be determined that the operation is abnormal, and the reverse rotation drive of the motor 12 is quickly stopped to prevent an overload from acting on the tap T. T2 can be prevented from being damaged.

  Further, the control means 50 determines whether or not the detection sensor 54 is operating normally when the motor 12 is driven in reverse rotation. The control means 50 sets a pair of on and off output from the detection sensor 54 as one pulse, starts counting pulses from the start of reverse rotation driving of the motor 12, and controls the number of detected pulses Pc of the counted pulses in advance. The backward reference pulse number Nc stored in the means 50 is compared. The reverse reference pulse number Nc is set based on the number of times the protrusion 52 of the detector 51 approaches the detection sensor 54 before the spindle shaft 20 moves backward from the forward end to the backward end. A value including an error is set in the number of times the protruding portion 52 approaches the detection sensor 54.

  The comparison between the detection pulse number Pc and the backward reference pulse number Nc is performed every time the detection sensor 54 counts pulses (step S13). If the detected pulse number Pc is equal to or smaller than the backward reference pulse number Nc as a result of comparison between the detected pulse number Pc and the backward reference pulse number Nc (No in step S13), is the backward end detecting means 59 turned on? (Yes in step S15) Or until the detection pulse number Pc exceeds the reverse reference pulse number Nc (Yes in step S13), the reverse rotation driving of the motor 12 is continued.

  If the detected pulse number Pc exceeds the reverse reference pulse number Nc before the backward end detecting means 59 detects ON, that is, before the spindle shaft 20 reaches the backward end (Yes in step S13). Then, it is determined that the detection sensor 54 is abnormal, and the rotation drive of the motor 12 is stopped (step S14). Thereby, the tapping process defect to the workpiece | work resulting from the malfunction of the detection sensor 54 can be prevented beforehand.

  Then, when the backward end detecting means 59 is turned on (Yes in Step S15), the control unit 50 stops the reverse rotation driving of the motor 12 (Step S14) and determines whether or not the brake of the motor 12 is operating normally. A determination is made (step S17).

  The control means 50 detects the excessive return movement amount at which the spindle shaft 20 has stopped after passing through the backward end, and determines whether or not the brake is abnormal based on the excessive return movement amount. The control means 50 takes a pair of on and off output from the detection sensor 54 as one pulse, and the pulse is generated when the spindle shaft 20 reaches the retracted end and the retracted end detecting means 59 is turned on by reverse rotation driving of the motor 12. Start counting.

  Then, the number of detected pulses Pd counted until the spindle shaft 20 stops retreating is compared with an excessive return allowable value Nd stored in the control means 50 in advance. If the detected pulse number Pd exceeds the allowable return value Nd (Yes in Step S17), it is determined that the brake of the motor 12 is abnormal (Step S16), and the tapping process is stopped or an error message is displayed. Make calls, turn on warning lights, etc.

  If the detected pulse number Pd is less than or equal to the allowable return value Nd (No in step S17), it is determined that the brake of the motor 12 is operating normally, and the tapping process is finished (end). . Thereby, the female screw stand for the workpiece W is finished, and the screw hole is completed.

  According to the tapping apparatus 1 having the above configuration, when the operation is normal, the tap holder 40 moves forward while rotating forward and moves backward while rotating backward. Therefore, the protrusion 52 of the detector 51 repeatedly approaches and separates from the detection sensor 54 according to the rotation of the tap holder 40, and the detection sensor 54 alternately outputs on and off at predetermined intervals, and the on / off interval Ta, Tb is shorter than the forward reference interval Tf and the backward reference interval Tr.

  On the other hand, when the rotation of the tap holder 40 stops due to the tap T biting into the screw hole of the workpiece, the protruding portion 52 of the detector 51 is either in a state of approaching or separated from the detection sensor 54. The output of the detection sensor 54 is maintained either on or off.

  Further, if the advancement of the tap T is hindered due to reasons such as the screw pilot hole W1 not being formed in the workpiece W, a load in the thrust direction acts on the tap T, and the tap holder 40 resists the urging force of the coil spring 24. Then, it moves in a contracting direction with respect to the spindle shaft 20, the positions of the detector 51 and the detection sensor 54 are shifted in the axial direction, and the output of the detection sensor 54 is kept off.

  Further, when the approach and separation of the protrusion 52 cannot be detected due to a failure of the detection sensor 54, the output of the detection sensor 54 is maintained either on or off. Accordingly, the on / off intervals Ta and Tb are longer than the forward reference interval Tf and the reverse reference interval Tr.

  Therefore, the control unit 50 compares the on / off interval Ta of the detection sensor 54 with the forward reference interval Tf, and also compares the on / off interval Tb with the reverse reference interval Tr to determine the work abnormality of the tapping process. Can do.

  Further, according to the tapping apparatus 1 having the above configuration, the control unit 50 starts counting pulses from the start of the forward rotation driving of the motor 12 with one pair of ON and OFF output from the detection sensor 54 as one pulse. The number of detected pulses Pa of the counted pulses and the number of times the protrusion 52 of the detector 51 approaches and separates from the detection sensor 54 before the spindle shaft 20 moves from the backward end to the forward end are set in advance. The forward reference pulse number Na is compared. If the detected pulse number Pa exceeds the forward reference pulse number Na before the forward end detecting means 58 detects ON, that is, before the spindle shaft 20 reaches the forward end, the detection sensor 54 is abnormal. Can be determined.

  Similarly, the control means 50 sets the pair of on and off output from the detection sensor 54 as one pulse, starts counting pulses from the start of reverse rotation driving of the motor 12, and detects the number of detected pulses Pc of the counted pulses. And the backward reference pulse number Nc set in advance as the number of times the protrusion 52 of the detector 51 approaches and separates from the detection sensor 54 before the spindle shaft 20 moves from the forward end to the backward end. If the detection pulse number Pc exceeds the reverse reference pulse number Nc before the backward end detecting means 59 detects ON, that is, before the spindle shaft 20 reaches the backward end, the detection sensor 54 is abnormal. Can be determined.

  Therefore, the control means 50 determines the sensor abnormality of the detection sensor 54 by comparing the detected pulse number Pa with the forward reference pulse number Na and comparing the detected pulse number Pd with the reference pulse number Nd. Can do.

  Furthermore, according to the tapping apparatus 1 having the above-described configuration, the control unit 50 sets the pair of on and off output from the detection sensor 54 as one pulse and drives the spindle shaft 20 to the forward end by driving the motor 12 to rotate forward. When reaching and the forward end detecting means 58 is turned on, the pulse counting is started. Then, the detected pulse number Pb counted until the forward movement of the spindle shaft 20 is stopped and the overshoot allowable value Nb previously stored in the control means 50 are compared, and the detected pulse number Pb exceeds the overshoot allowable value Nb. If so, it is determined that the brake of the motor 12 is abnormal.

  Similarly, the control means 50 sets the pair of on and off output from the detection sensor 54 as one pulse, and the spindle shaft 20 reaches the backward end by the reverse rotation driving of the motor 12, and the backward end detecting means 59 is turned on. To start counting pulses. Then, the detection pulse number Pd counted until the backward movement of the spindle shaft 20 is compared with the excessive return value Nd stored in the control means 50 in advance, and the detection pulse number Pd is set to the excessive return value Nb. If it exceeds, it is determined that the brake of the motor 12 is abnormal.

  Therefore, the control means 50 can determine the brake abnormality of the motor 12 by comparing the detection pulse Pb with the overshoot allowable value Nb and by comparing the detection pulse Pd with the overreturn allowable value Nd. .

  The tapping apparatus 1 having the above-described configuration can determine a tapping process work abnormality, a sensor abnormality of the detection sensor 54, and a brake abnormality of the motor 12 by a simple configuration of the detector 51 and the detection sensor 54. Moreover, it can be retrofitted to a conventional apparatus and can be easily implemented.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above-described embodiment, the case where the detection sensor 54 is a proximity switch has been described as an example. However, a limit that outputs ON and OFF by causing the contact to contact the protruding portion 51 and the recessed portion 52 of the detector 51. It may be a switch.

  In the above-described embodiment, the case where the detector 51 forms the four protruding portions 52 and the four recessed portions 53 alternately and continuously has been described as an example. However, the number of the protruding portions 52 and the recessed portions 53 is described. It is sufficient that there is at least one each, and the size extending over a predetermined angle range along the rotation direction can be variously set. Therefore, for example, a part of the disk shape may be cut out at only one place, the cutout part may be a recessed part, and the other part may be a protruding part. Further, a rod-shaped member such as a bolt may be projected from the spindle shaft 20 outward in the radial direction, the tip portion of the rod-shaped member may be formed as a protruding portion, and the periphery thereof may be formed as a recessed portion.

It is a whole view explaining the structure of the tapping processing apparatus concerning this Embodiment. It is the XX sectional view taken on the line of FIG. It is a flowchart explaining a tapping processing method. It is a figure explaining operation | movement of the tapping processing apparatus with respect to the workpiece | work in which the appropriate screw pilot hole is formed. It is a figure explaining operation | movement of the tapping processing apparatus with respect to the workpiece | work in which the screw pilot hole is not formed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tapping processing apparatus 11 Rotating shaft 12 Motor (rotation drive part)
20 Screw feed mechanism (feed moving part)
24 Coil spring (biasing means)
30 Spindle shaft 40 Tap holder 50 Control means 51 Detector 52 Protruding part 53 Recessed part 54 Detection sensor W Work W1 Screw pilot hole T Tap T1 Shank part T2 Screw part

Claims (8)

A base part;
A rotating shaft rotatably supported by the base portion;
A rotation drive unit for rotating the rotating shaft forward and backward, and
A spindle shaft that is integrally rotatable with the rotating shaft and is movably connected in the axial direction of the rotating shaft;
A feed movement unit that rotatably supports the spindle shaft on the base unit and moves forward and backward at a feed pitch according to forward rotation and reverse rotation;
It rotates integrally with the spindle shaft and is connected to the spindle shaft so as to be movable in the axial direction, and is provided so as to extend and contract in the axial direction at a position forward of the front end portion of the spindle shaft. A tap holder capable of holding a tap having the same feed pitch as the feed moving unit;
A biasing means that is interposed between the spindle shaft and the tap holder and biases the tap holder in the extending direction;
Protruding portions provided on the tap holder and protruding outward in the radial direction of the tap holder and concave portions recessed inward in the radial direction of the tap holder are alternately formed along the rotation direction of the tap holder. And a detector to
The base portion is supported so as to be able to advance and retreat in synchronization with the spindle shaft, and is arranged at a position facing the detector at a radially outer position of the tap holder with respect to the detector when the tap holder is extended. A detection sensor that outputs ON when approaching the projecting portion and outputs OFF when separated from the projecting portion;
And a tapping device that controls the rotation drive unit based on the output of the detection sensor. The control means includes
Measure the on-off interval of on and off output from the detection sensor in the positive rotation drive of the rotation drive unit,
Compare the measured on-off interval with a preset forward reference interval,
2. The tapping apparatus according to claim 1, wherein when the on / off interval exceeds the forward reference interval, it is determined that the operation is abnormal, and the forward rotation driving by the rotation driving unit is stopped. The control means includes
Measure the on-off interval of on and off output from the detection sensor in the reverse rotation drive of the rotation drive unit,
Compare the measured on-off interval with a preset reverse reference interval,
3. The tapping apparatus according to claim 1, wherein when the on / off interval exceeds the retreat reference interval, it is determined that the operation is abnormal, and reverse rotation driving by the rotation driving unit is stopped. The control means includes
A pair of on and off output from the detection sensor is set as one pulse, and counting of the pulse is started from the start of forward rotation driving of the rotation driving unit,
The number of detected pulses of the counted pulse, and a forward reference pulse number set based on the number of times the protrusion of the detector approaches the detection sensor while the spindle shaft advances from the backward end to the forward end. Compare
2. The sensor abnormality of the detection sensor is determined when the number of detected pulses exceeds the number of forward reference pulses before the spindle shaft advances from a backward end and reaches a forward end. The tapping apparatus according to any one of to 3. The control means includes
A pair of on and off output from the detection sensor is set as one pulse, and counting of the pulse is started from the start of reverse rotation driving of the rotation driving unit,
The number of detected pulses of the counted pulse and the number of reverse reference pulses set based on the number of times the protrusion of the detector approaches the detection sensor while the spindle shaft is retracted from the forward end to the backward end. Compare
2. The sensor abnormality of the detection sensor is determined by the detection pulse number exceeding the backward reference pulse number before the spindle shaft moves backward from the forward end and reaches the backward end. The tapping apparatus of any one of -4. The control means includes
The pulses counted from the time when the spindle shaft reaches the forward end by forward rotation driving of the rotational drive unit until the forward movement of the spindle shaft stops, with a pair of ON and OFF output from the detection sensor as one pulse. Compare the number of detected pulses and the preset overshoot tolerance,
The tapping apparatus according to any one of claims 1 to 5, wherein when the number of detected pulses exceeds the overshoot allowable value, it is determined that the brake of the rotation drive unit is abnormal. The control means includes
The pulse counted from the pair of on and off output from the detection sensor as one pulse, until the spindle shaft reaches the retracted end by the reverse rotation driving of the rotation driving unit until the spindle shaft advances. Compare the number of detected pulses and the preset allowable return value,
The tapping apparatus according to any one of claims 1 to 6, wherein when the number of detected pulses exceeds the excessive return allowable value, it is determined that the brake of the rotation drive unit is abnormal. The tapping apparatus according to any one of claims 1 to 7, wherein the detection sensor outputs an off state when the tap holder is contracted and the opposing of the detection element is released.

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